The invention relates to hydraulic axial piston machines, in particular hydraulic axial piston machines of the swash plate or bent axis type of construction, both in the form of a constant unit or a displacement unit in the embodiments thereof as hydraulic pumps or hydraulic motors. The invention relates here, by way of example, to displacement axial piston machines, in which the supply volume can be adjusted by swiveling displacement devices, such as swash plates or bent axes.
Hydraulic axial piston machines have a rotating cylinder block unit which is usually of cylindrical design. In the circumferential direction of the cylinder block unit cylinder bores are provided rotationally symmetrically parallel to the axis of rotation of the cylinder block unit in which bores displacing pistons are arranged axially oriented. The feet of the displacing pistons are usually supported on a pressure plate which, for example in the case of axial piston machines of the swash plate type of construction, is the swash plate. In case of axial piston machines of the bent axis type of construction, the pressure plate can be integrated into the drive or driven shaft of the axial piston machine or else formed integrally therewith. On the axially opposite side of the pressure plate, a closing plate takes over the support of the cylinder block unit in the axial direction, and therefore the displacing pistons can execute a predeterminable stroke per revolution of the cylinder block unit. By means of the stroke of the displacing pistons in the cylinder bores, a delivery volume or displacement volume of a hydraulic fluid flows through the cylinder block unit and sets the latter—in the case of a hydraulic motor—into rotation. If—in the case of a hydraulic pump—the cylinder block unit is driven, the stroke of the displacing pistons in the cylinder bores produces a delivery volume. A drive or driven shaft via which the cylinder block unit is driveable in a rotatory manner is connected to the cylinder block unit for rotation therewith. In the case of a hydraulic motor, the driven shaft is set into a rotational movement via the cylinder block unit, which is acted upon by pressurized fluid.
So that the rotating parts or the pistons, which are acted upon by hydraulic fluid and are moved in a translatory manner, are held or supported between the pressure plate/swash plate and the closing plate in the position corresponding in each case to the operating state, a housing is conventionally provided, said housing taking on this function and, in particular, holding the supporting elements/abutments, i.e., in particular, the pressure plate/swash plate and closing plate—in the relative positions thereof with respect to one another. The housing also ensures that the drive or driven shaft can be mounted rotatably, wherein said drive or driven shaft, supported axially by the housing, is generally accommodated so as to be rotatable via rolling or plain bearings. The housing furthermore ensures that the pressure plate, on which the displacing pistons are supported, is fixed in the relative position thereof with respect to the rotating cylinder block unit. Depending on the type of construction (swash plate or bent axis type of construction), it is possible for the pressure plate to be swiveled relative to the cylinder block unit or for the cylinder block unit to be swiveled relative to the pressure plate. The drive or driven shaft is generally invariable in its the relative position in the housing and is customarily only rotatable about the longitudinal axis thereof and is otherwise generally immovable axially.
Therefore the housing has further the function of absorbing supporting forces which occur in particular during a swiveling or pivoting operation for changing the delivery volume of the axial piston machine. The forces necessary for supporting the moving components are generally all the more higher, the greater the deflection of the displacement device of the axial piston machine is. The housing therefore has to be designed to be correspondingly stable and robust so that said forces can be reliably absorbed. However, a large space requirement and a high weight are customarily also associated with a solid design of the housing.
The housing furthermore protects the rotating and moving machine parts of the axial piston machine from soiling and other environmental influences. The housing frequently also serves as a liquid reservoir, wherein, even in the case of dry-case motors or dry-case pumps, a leakage liquid reservoir is frequently formed in the housing, which requires an additional amount of space.
The housing therefore has a supporting function and also a protective function for the components of the axial piston machine that are necessary for operating the axial piston machine. The housings of axial piston machines are therefore customarily bulky and heavy and cause high costs for the production of axial piston machines. The provision and installation of the axial piston machine in a housing also requires a multiplicity of working steps which additionally cause high costs. As already explained above, for the reliable operation of an axial piston machine, the moving and rotating parts have, however, to be held in certain predetermined positions relative to one another so that the operation of the axial piston machine is ensured.
In a multiplicity of uses, axial piston machines are connected to mechanical gearings in order to drive working machines or so that an axial piston machine itself can be driven in order to produce a hydraulic fluid flow. Since gearings are usually also provided with a housing, onto which the housing of an axial piston machine is flanged, two separate housings which have to be coordinate with each other are generally necessary in the prior art. In particular, the interface between axial piston machine and gearing has to be designed here in such a manner that a safe and reliable interaction of the axial piston machine with the gearing is ensured. The surfaces, centering means and receptacles which are necessary here for the fastening and centering, together with the necessary production tolerances associated therewith, cause high costs for the production of the two housings—that of the gearing and that of the axial piston machine.
DE 10 2011 009537 discloses a hydrostatic machine, in particular an axial piston machine with a housing. The housing has an inner housing part for receiving the force flux, an outer housing part for sealing and damping, and a housing base. The inner housing part is designed as a supporting frame with struts. A driving shaft passes coaxially through the housing base on the drive side and through a swash plate on the output side and is connected to a cylinder drum for rotation therewith. The driving shaft passes at least partially only through the inner housing part and through the housing base and is mounted rotatably in the inner housing part. The inner housing part is provided for absorbing the dynamic forces occurring in the hydrostatic working mode of the axial piston machine, for which purpose said housing part has to be of high strength. Substantially similar designs of axial piston machines can also be gathered from DE 42 03 619 A1 and DE 1 118 010 A, in which a mechanically robustly designed “yoke” is used instead of the inner housing part.
It is therefore object of the invention to provide a device for an axial piston machine, said device replacing a housing for the axial piston machine to the effect that the axial piston machine can be connected as an assembly to a gearing, wherein both the gearing and the axial piston machine are accommodated in one and the same housing. Furthermore, a device is to be provided, making it possible to transport, store and fit axial piston machines without housings in a simple and uncomplicated manner. The assemblies of closing plate, cylinder block unit with displacer pistons arranged therein and drive or driven shaft are to be positioned with respect to one another in such a manner that said assemblies are securely held and arranged preferably in a functionally ready position. It is a further object of the invention to provide a device which fixes the movable parts of an axial piston machine and hold said parts in position in such a manner that a test run of the axial piston machine at low forces or loads is possible.
The object of the invention is achieved by a mounting structure according to Claim 1, wherein specific embodiments are indicated in the dependent claims. By the further independent claims an axial piston machine which is functionally ready for a test run and a hydromechanical functional unit consisting of an axial piston machine and a gearing with just a common housing are provided.